Drafting-machine



A. c. LA MAYjif DRAFTING MACHINE. I APPLICATION FILED NOV. 6, |916 A 1,336,241 Patented Apr. 6, 1920.

2 SHEETS-SHEET l.

UNITED STATES PATEN T OFFICE.

ARTHUR C. LA MAY, OF ROCHESTER, NEW YORK; BRIDGET LA MAY ADMINISTRATRIX OF SAID ARTHUR C. LA MAY, DECEASED.

DRAFTING-MACHINE.

Application filed November 6, 1916.

To all 'LU/tom t may concern.'

Be it known that I, ARTHUR C. LA MAY, a citizen of the United States, residing at Rochester, in the county of Monroe and State of New York, have invented certain new and useful Improvements in Drafting- Machines, of which the following is a specification.

rIhe object of this invention is to provide a new and improved form of drafting machine to take the place of a T square and triangles.

This and other objects of the invention will be fully illustrated in the drawings, described in the specification and pointed out in the claims at the end thereof.

In the accompanying drawings, Y

Figure 1 is a top plan view of the drafting machine.

Fig. 2 is a cross-section through the cariage of the protractor on the lineA 2"--2X of fig. l.

Fig. 3 is a cross-section through the end of the moving member of the parallel bars, the section being taken on the line 3 3X of Fig. 1.

Fig. 4 is a cross-section through the line 4X-4X of Fig. 2, showing the spacing device for measuring the movement of the carriage of the protractor, the spacing device being shown raised or disengaged.

Fig. 5 shows the same as Fig. 4, except that the spacing device is in engaging position.

Fig. 6 is a section on the' line (SX-6X of Fig. l.

Fig. 7 Fig. l.

Fig. 8 is a plan view of a modified form of my improved drafting machine.

Fig. 9 is a view of the' modified form of drafting machine of Fig. 8 showing the parts in different positions.

In the drawings like reference numerals indicate like parts.

In the drawin s are shown two parallel bars of which re erence numeral 1 indicates the stationary bar and 2 indicates the movable bar. The stationary bar is perforated as indicated at 3 with openings through which thumb tacks 4 extend into engagement with the drafting board below. These thumb tacks hold the stationary bar rigidly in position on the drafting board. The thumb tacks 4, 4 are carried on the ends of is a section on the line 7*- X of Specification of Letters Patent.

Patented Apr. 6, 1920.

Serial No. 129,741.

the spring bar 5, which is riveted to the stationary bar 1 at 6, 6.

This spring bar holds the thumb tacks 4, 4 in position above the openings in the member 1 so that they will not become lost and are always in position to be easily engaged with the drafting board.

Each of the bars 1 and 2 is bent to the shape shown in section in Figs. 2, 3 and 6 in which each bar is made with a flat base 7 having a flange 8 extending upwardly therefrom on the rear edge thereof, with a channel 9 extending along the upper edge of the flange. This channel is shown round in section but it may have any other form desired. The channel is left with a narrow slot 10 therein. In the channel on the bar 1 are mounted the heads 1l and 12, one of these, preferably 11., being fastened rigidly in the channel and the other one 12 being mounted so that it is free to slide therein.

On the bar 2 the heads 13 and 14 are mounted on the outside of the channel, the head 13 being rigid thereon and the head 14 being free to slide thereon. The heads 12 and 13 are connected by the link 15 and the heads 11 and 14 are connected by the link 16. These links are pivoted to each other at 17, and are so related to the parallel bars that they permit the bars to move toward and from each other and hold the bars at all times in a position substantially parallel to each other.

Mounted to slide on the bar 2 is the protractor 18 shown in section in Fig. 2. This protractor comprises a plate 19 and has a head 20 formed on the edge thereof to fit in the channel 9 of the parallel bar 2, the plate being free to travel along the channel. On the forward side of the protractor is provided a circular scale 21 having notches formed therein suitably spaced apart to indicate angles. Mounted to swing radially on the protractor is the scale 22 which scale is provided with a dog 23 that is adapted to engage with the notches in the circular scale 21 and hold the scale 22 in any desired angular position.

It will be seen that the protractor can be moved along the parallel bar 2, and the swinging scale 22 can be set at any desired angle to the bar 2, and thus any desired combination of positions of angles may be secured.

The bar 2 is perforated as indicated at 24, and the protractor is provided with a spacing device 25 for the purpose of engaging with the perforations 24 to hold it firmly in successive positions. This spacing device consists of a dog mounted to slide in a cup 26 and is pressed downwardly therein by a spring 27. On top the dog carries a pin 28 that engages with suitable recesses formed in the rim of the cup at different elevations by which the dog is held in different elevations so that it will engage with or be disengaged from the recesses in the bar 2. The dog is beveled in one direction and can be turned either to the right or the left so as to permit it to run freely in either direction desired, it being intentional to use this dog in advancing the protractor through successive steps in making section lines. Such section lines are shown in connection with Fig. 1 in which the vertical lines are spaced an eighth of an inch apart and the diagonal lines shown in two sets are spaced closer together according to the angle at which the protractor is set. The plate 19 is provided with an opening therein through which the scale on the edge of the bar 2 may be observed while the protractor is being moved. A pointer is provided in this opening which indicates the position of the protractor on the scale.

The swinging bar 22 is shown provided with openings 25 in which the pencil point may be inserted and the bar can then be swung, enabling the operator to draw a segment of a circle, thus using the protractor as a compass to hold the plate 19 of the protractor stationary while a segment is being drawn. A pin 29 is provided at the center of rotation of the swinging arm22, which pin can be pushed down into engagement with the drafting board to hold the center of the swinging arm fixed against movement.

On the ends of the parallel bar 2 I provide buttons 30 and 31 which hold the ends of the bar slightly raised above the paper so that a ruling pen can be used to better advantage with the sliding bar. A similar button 32 is used on the end of the swinging arm 22 of the protractor. The bars are slotted so that the buttons can be easily inserted and removed. Each button consists of two rounded heads connected by a short pin as shown in Fig. 7.

On the head 14 is provided a set screw 33 by which it may be clamped in place on the bar 2 so that it cannot slide thereon. This in turn will hold the bar 2 in place and keep it from sliding.

In Fig. 8 I have shown a modified form of my drafting machine in which 40 indicates the stationary bar having a channel 41 formed thereon on which slides a head 42. On the head 42 is formed a circular scale 43 having notches thereon. n the scale is pivotally mounted the bar 44 which may be swung to any position. On the bar 44 is mounted a head 45 having a circular scale thereon also provided with notches. On this circular scale is mounted to swing a bar 47.

As shown in Fig. 8 the bar 44 is shown in position parallel to the bar 40 and the bar 47 is at right angles to both the bars 40 and 44. The bar 44 may be swung to the position shown in Fig. 9 and the bar 47 may be placed thereon at an angle thereto and parallel to the bar 40. The bar 47 can then be moved up and down on the bar 44 for the purpose of drawing lines parallel to the bar 40. Lines at an angle to the bar 40 may be drawn along the bar 44, the position of which may be changed as may be required. Lines at an angle may also be drawn along the bar 47 which can also be placed at angles and perpendicular lines ma be drawn along the bar 47 as shown in iig. 8, or along the bar 44 which may be swung to a vertical position for that purpose.

It is also apparent that the bar 40 may be substituted in Fig. 1 for the bar 2, being then connected with the stationary bar 1 by the links 15 and 16 in which case it can be moved up and down as a parallel bar and the swinging hars 44 and 47 may still be used in connection therewith. Such a modication is' shown in Fig. 9.

I claim.

1. A ruling bar having an open slot therein, a button for engaging with said slot and presenting a raised surface below said bar.

2. In a drafting machine the combination of a bar, a channel formed on said bar, a plate mounted to slide in said channel, a bar mounted to swing on said sliding plate, a pin passing through the center of rotation of said bar to engage with the drafting board to hold said sliding plate in fixed position.

3. In a drafting machine the combination of a bar, a channel formed on said bar, a plate mounted to slidein said channel, said bar having perforations therein, a spacing device carried on said plate for engaging with each of said perforations in turn.

4. In a drafting machine the combination of a bar, a channel formed on said bar, a plate mounted to slide in said channel, said bar having perforations therein, a spacing device carried on said plate for engaging with each of said perforations in turn, said spacing device being reversible.

In testimony whereof I affix my signature in presence of a witness.

ARTHUR C. LA MAY.

Witness ELEANOR M. CoRcoRAN. 

